This project is designed to investigate the effects of drugs of abuse on affective responses to stimuli with positive or negative emotional valence. The studies explore the hypothesis that drugs modulate responses to affective stimuli, and that these effects, in turn, influence the drugs' subjective or reinforcing effects. We will study bidirectional interactions between acute effects of stimulants, alcohol and cannabinoids on affective responses. The studies focus in particular on affective responses to stimuli with social content, to investigate the idea that drugs influence the perception and valence of social stimuli. We will assess the effects of drugs on responses to positive or negative visual images, including images with social or nonsocial content. In addition, we will investigate drug the effects of drugs in real-life positive or negative social situations. In all studies we will compare these emotional responses in men and women. This innovative approach bridges the area of neuropsychopharmacology with affective neuroscience, and if successful, will extend our understanding of the processes that lead to compulsive drug-seeking behavior. PUBLIC HEALTH RELEVANCE: It is usually thought that people use and abuse drugs because the drugs produce feelings of wellbeing, but drugs also may influence behavior by making emotionally positive stimuli or events appear to be more positive, or by making negative stimuli or events less negative. We will investigate the direct effects of drugs on emotional responses, using both pleasant and unpleasant stimuli, and social and nonsocial stimuli. We will study social content because social behavior and drug rewards share some of the same brain circuits, and we will compare the drugs' effects on emotional responses in men and women because there may be sex differences in these effects.